Temperature Monitoring during Laser Beam Forming of Steel Sheets

2014 ◽  
Vol 622-623 ◽  
pp. 811-818
Author(s):  
Stephen Akinlabi ◽  
Esther Titilayo Akinlabi
Keyword(s):  
Laser Beam ◽  
Temperature Monitoring ◽  
Laser Forming ◽  
Great Promise ◽  
Beam Forming ◽  
Measured Temperature ◽  
Data Logger ◽  
Forming Process ◽  
Line Energy ◽  
Steel Sheets

Laser Beam Forming is a flexible manufacturing process with great promise for sheet and metal forming, hence, considered as a novel manufacturing method for forming and shaping of metallic components. Being a thermo-mechanical forming process that enables parts or components to be formed with external heat of a laser beam, it is important to monitor and measure the temperature during the laser forming process in order to ensure the integrity of the processed components. This study reports on the temperature monitoring and measurement during laser beam forming process of steel sheets. The experimental design followed the L-27 Taguchi Orthogonal Array. The temperature of nine sets of samples laser beamed formed at different process parameters were monitored using the thermocouple data logger. The temperature for all the components formed at the nine parameter windows were analysed during the process. Hence, it was observed that the measured temperature increases with the increasing line energy during the laser beam forming process.

Affected Characteristics Analysis of the Pulsed Laser Forming of Metal Sheet

2008 ◽  
Vol 375-376 ◽  
pp. 333-337
Author(s):  
Li Jun Yang ◽  
Yang Wang
Keyword(s):  
Laser Beam ◽  
Pulsed Laser ◽  
Metal Sheet ◽  
Grain Structure ◽  
Experimental Result ◽  
Laser Forming ◽  
Forming Process ◽  
Grain Orientations ◽  
Characteristics Analysis ◽  
Relationship Of

Laser forming of metal sheet is a forming technology of sheet without a die that the sheet is deformed by internal thermal stress induced by partially irradiation of a laser beam. In this paper, the bending behavior of common stainless steel 1Cr18Ni9 sheet is studied after being irradiated by straight line with a Nd:YAG pulsed laser beam. The aim of the investigation is to find out the relationship of the physical behaviors of heat affected zone (HAZ) with the pulse parameters of the laser. Through the analysis of the fundamental theory of pulsed laser affected, this paper shows the affected characteristics of metal sheet with pulsed laser forming. The results show that the microstructure of HAZ of pulsed laser scanned is layered, and the micro-hardness is improved than that in matrix. The microstructures show that the deformed grain structure is inhomogeneous, that caused the grain sizes and grain orientations in HAZ to become different. By qualitative analysis of experimental result, the conclusion obtained may provide basis for theoretical investigation and possible industrial application of laser forming process in the future.

scholarly journals Consideration of Absorption Coefficient Changes in Numerical Simulations of Laser Forming

2019 ◽  
Vol 44 (1) ◽  
pp. 1-5
Author(s):  
Helge Kügler ◽  
Frank Vollertsen
Keyword(s):  
Absorption Coefficient ◽  
Laser Beam ◽  
Numerical Simulations ◽  
Surface Oxidation ◽  
Laser Beams ◽  
Laser Forming ◽  
Beam Forming ◽  
Work Piece ◽  
Solid State Lasers ◽  
Co2 Lasers

Material processing with laser beams is well-known in nowadays production. Compared to CO2 lasers, modern solid state lasers are, amongst others, popular because of higher energy efficiency and higher absorption when metals like steel and aluminum are irradiated. However, the absorption of metals is not only dependent on the chemical composition of the work piece metal and the laser beam wavelength. Previous investigations determined the oxidation of the surface as an influence on laser beam absorption changes due to multiple irradiation. In this study, a method is presented for considering the absorption coefficient changes caused by surface oxidation in numerical simulations. Reproductions of single trajectories were assigned with appropriate absorption coefficients calculated from a function generated by reference tryouts. With the described approach, benefits are gained for numerical simulations of laser beam forming (like bending) and other processes with an iterative heat input.

An Experimental Study on Bending Process of AISI 304 Steel Sheets by using Diode Laser Forming

2014 ◽  
Vol 1 (1) ◽  
pp. 14-30
Author(s):  
Alfonso Paoletti
Keyword(s):  
Laser Beam ◽  
Diode Laser ◽  
Process Parameters ◽  
Laser Forming ◽  
Laser Bending ◽  
Aisi 304 ◽  
Steel Sheets ◽  
Metal Sheets ◽  
Bending Process ◽  
Aisi 304 Steel

Laser bending is a promising technique utilised in order to deform metal sheets that offers the advantage of requiring no hard tooling and no external forces, thus reducing cost and increasing flexibility. Laser forming involves a complex interaction of many process parameters, ranging from those connected with the irradiation of the laser beam to those regarding the thermal and mechanical properties of the workpiece material. The present work is focused on the laser bending of AISI 304 steel sheets by using of a diode laser. The influence of process parameters, such as the power of laser beam and the scanning speed as well as the metal sheet thickness on the bending angle has been taken into account. The investigation has also analysed the effect of rolling direction of the metal sheets and the conditions of cooling on the bending process.

scholarly journals A comparative investigation of the efficacy of CO2 and high-power diode lasers for the forming of EN3 mild steel sheets

2002 ◽  
Vol 216 (11) ◽  
pp. 1481-1491 ◽  
Author(s):  
J Lawrence
Keyword(s):  
Mild Steel ◽  
High Power ◽  
Traverse Speed ◽  
Comparative Investigation ◽  
Laser Forming ◽  
Bending Angle ◽  
Line Energy ◽  
Steel Sheets ◽  
Power Diode ◽  
Bending Angles

A comparative investigation of the effectiveness of a high-power diode laser (HPDL) and a CO2 laser for the forming of thin-section EN3 mild steel sheet has been conducted. The buckling mechanism was identified as the laser forming mechanism responsible for induced bending. For both lasers it was found that the induced bending angles increased with an increasing number of irradiations and high laser powers, while decreasing as the traverse speed was increased. Also, it was apparent from the experimental results that the laser bending angle was only linearly proportional to the number of irradiations when the latter was small due to local material thickening along the bend edge with a high number of irradiations. Owing to the mild steel's greater beam absorption at the HPDL wavelength, larger bending angles were induced when using the HPDL. However, under certain conditions the performance of the CO2 laser in terms of induced bending angle was seen to approach that of the HPDL. Nevertheless, similar results between the two lasers were only achieved with increasing irradiations; thus it was concluded that the efficacy of the HPDL was higher than that of the CO2 laser insofar as it was more efficient. From graphical results and the employment of an analytical procedure, the laser line energy range in which accurate control of the HPDL bending of the mild steel sheets could be exercised efficiently was found to be 53 J/mm < P/ v < 78 J/mm, while for the CO2 laser the range was 61 J/mm < P/ v < 85 J/mm.

Effect of Scan Velocity on Resulting Curvatures during Laser Beam Bending of AISI 1008 Steel Plates

2011 ◽  
Vol 299-300 ◽  
pp. 1151-1156 ◽  
Author(s):  
Stephen Akinlabi ◽  
Tshilidzi Marwala ◽  
Esther Titilayo Akinlabi ◽  
Mukul Shukla
Keyword(s):  
Laser Beam ◽  
Low Carbon Steel ◽  
Microstructural Characterization ◽  
Steel Plates ◽  
Beam Forming ◽  
Low Carbon ◽  
Forming Process ◽  
Grain Structures ◽  
Beam Bending ◽  
Different Shapes

Forming is a flexible process, by which a variety of different shapes can be produced through mechanical, thermo-mechanical, or thermal [Laser Beam Forming] process. Laser beam forming [LBF] process has been successfully applied to a variety of sheet metal components thereby plastically deforming it. This paper investigates the producing effect of scan velocity on the resulting curvatures and resulting properties of the bent components. The results show that three different curvatures (120, 180 and 240 mm) of 4 mm AISI 1008 low carbon steel plate was successfully produced under an optimized set of process parameters and a direct relationship was observed between the scan velocity and the resulting curvatures. Furthermore, microstructural characterization revealed that the grain structures of the irradiated surfaces are refined with cooling than the bottom due to the nucleation rate of new grains formed at the irradiated surface.

Curved Surfaces Forming of Sheet Material by Laser Irradiation

2014 ◽  
Vol 1017 ◽  
pp. 788-793
Author(s):  
Keisuke Kishida ◽  
Hideki Aoyama ◽  
Naohisa Mastushita ◽  
Akihiko Ushimaru
Keyword(s):  
Laser Beam ◽  
Laser Irradiation ◽  
Degrees Of Freedom ◽  
Sheet Material ◽  
Fem Analysis ◽  
Laser Forming ◽  
Curved Surfaces ◽  
Line Energy ◽  
Forming Technology ◽  
Curvature Lines

Laser forming is a technology which can form sheet material such as steel and plastic by irradiating a laser beam on the surfaces of material. In the forming, it does not need costly dies and molds, and forming degrees of freedom are high. However, since the forming mechanisms are complex, complete forming technology for practical use has not been developed. The objectives of this paper are to explain phenomena of laser forming by experiments and FEM analysis and to develop a forming method of curved surfaces by laser forming. The phenomena are explained by the temperature change, stress change, and plastic strain change at a laser irradiation point which was obtained by FEM analysis. Line energy is proposed for explanation of laser forming phenomena to classify the forming mechanisms, and a method is proposed in order to form curved surfaces of sheet material by irradiating a laser beam on maximum and minimum curvature lines. The effectiveness of the method was verified by a basic experiment.

Laser Beam Forming: Experimental Investigation and Statistical Analysis of the Effects of Parameters on Bending Angle

2013 ◽  
Author(s):  
Stephen Akinlabi ◽  
Mukul Shukla ◽  
Tshilidzi Marwala
Keyword(s):  
Laser Beam ◽  
Process Parameters ◽  
Manufacturing Process ◽  
Steel Plate ◽  
Cooling Effect ◽  
Laser Forming ◽  
Maximum Effect ◽  
Beam Forming ◽  
Bending Angle ◽  
Bending Angles

Laser Beam Forming (LBF), a non-contact manufacturing process has become a viable manufacturing process for shaping of metallic components. The capability of LBF and bending demands more on experimental studies to identify optimized parameter settings and also establish the probable influence of process parameters on the response i.e. the resulting bending angles in the present work. The experiments on laser forming process of 3 mm steel plate were conducted using a 4.4 kW Nd: YAG laser (Rofin DY 044), at the Council for Science and Industrial Research - National Laser Centre (CSIR-NLC), Pretoria, South Africa. This paper investigates the effects of five important process parameters such as namely laser power, beam diameter, number of scan tracks, scan velocity and cooling effect on the resulting formed sample curvature. Statistical tools combined with the Taguchi robust Design of Experiment, based on the L-27 Taguchi Orthogonal array (TOA) have been used. The samples were successfully formed to different curvatures following the experimental design. Both the Taguchi analysis and Analysis of Variance (ANOVA) established that the number of scan irradiation had the maximum effect while cooling effect coolant flow had the least contribution on the bending angle of formed components. Regression analysis was also conducted on the experimental data and a linear model relating all the influencing parameters was developed with an R-square value of around 98% showing the goodness of fit of the model. The regression model confirms that the experimentally measured bending angles were in good agreement with the model predicted values. This model can ultimately be used to estimate the bending angle in LBF of 3 mm steel plate within the study range of parameters.

scholarly journals Investigation of Residual Stress in Laser Formed Mild Steel Plates Using Neutron Diffraction

2010 ◽  
Vol 652 ◽  
pp. 123-128 ◽  
Author(s):  
Stefan M. Knupfer ◽  
Anna Maria Paradowska ◽  
Oliver Kirstein ◽  
Andrew Moore
Keyword(s):  
Residual Stress ◽  
Neutron Diffraction ◽  
Residual Stresses ◽  
Mild Steel ◽  
Reference Sample ◽  
Longitudinal Direction ◽  
Steel Plates ◽  
Laser Forming ◽  
Forming Process ◽  
Line Energy

Forming of metal plates with a high-power laser beam is a flexible materials forming technique. Bending results from the establishment of a steep temperature gradient through the material thickness which leads to non-uniform thermal expansion/contraction and subsequently residual stresses. It is important to characterize these residual stresses as a function of process parameters such as line energy (LE) to optimize treatment conditions and to gain an insight into the mechanism of the formation of the final geometries. Non-destructive neutron diffraction measurements were carried out on ENGIN-X at ISIS and KOWARI at ANSTO to map the residual stress distribution around the heat affected zone (HAZ) of laser deformed mild steel plates for single and multiple passes as a function of line energy (LE), the primary laser forming process parameter. It was found that in the centre of the HAZ, longitudinal residual stresses are tensile and dominant, transverse stresses are predominantly tensile and normal stresses are compressive and close to zero. The residual strain in longitudinal direction increased with LE and number of passes until yielding. Even higher heat input decreased the magnitude of the cusp, but not its total height. The comparison of a stress-free reference sample, measured at both facilities, showed a small discrepancy in the lattice spacing corresponding to ~ 85 μstrain which is insignificant with respect to the experimental values measured.

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